import java.util.LinkedList;
import java.util.Queue;

public class BinaryTree {

    static class TreeNode {
        public char val;
        public TreeNode left;//左孩子的引用
        public TreeNode right;//右孩子的引用
        public TreeNode(char val) {
            this.val = val;
        }
    }

    //public TreeNode root;

    /**
     * 创建一棵二叉树 返回这棵树的根节点
     * @return
     */
    public TreeNode createTree() {

        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');

        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        E.right = H;
        return A;
    }

    // 前序遍历
    void preOrder(TreeNode root) {
        if(root == null) return;
        System.out.print(root.val+" ");
        preOrder(root.left);
        preOrder(root.right);
    }

    // 中序遍历
    void inOrder(TreeNode root){
        if(root == null) return;
        inOrder(root.left);
        System.out.print(root.val+" ");
        inOrder(root.right);
    }

    // 后序遍历
    void postOrder(TreeNode root){
        if(root == null) return;
        postOrder(root.left);
        postOrder(root.right);
        System.out.print(root.val+" ");
    }

    public static int sz =0;
    public int size(TreeNode root){
        if(root!=null){
            sz++;
        }else {
            return sz;
        }
        size(root.left);
        size(root.right);
        return sz;
    }

    public int size1(TreeNode root){
        if(root==null) return 0;
        return size1(root.left)+size(root.right)+1;
    }
    public static int leafSz = 0;
    public int getLeafTreeNode(TreeNode root){
        if(root==null) return 0;
        if(root.left==null&&root.right==null) {
            leafSz++;
        }
        getLeafTreeNode(root.left);
        getLeafTreeNode(root.right);
        return leafSz;
    }

    public int getLeafTreeNode1(TreeNode root){
        if(root==null) return 0;
        if(root.left==null&&root.right==null) {
            return 1;
        }
        return getLeafTreeNode1(root.left)+getLeafTreeNode1(root.right);

    }

    public int getLevelTreeNode(TreeNode root,int k) {
          if(root==null) return 0;
          if(k==1) return 1;
         return getLevelTreeNode(root.left,k-1)+getLevelTreeNode(root.right,k-1);
    }

//    /*
//    获取二叉树的高度
//    */
//    int getHeight(TreeNode root) {
//          if(root==null) return 0;
//          return getHeight(root.left)>getHeight(root.right)
//                  ?getHeight(root.left)+1:getHeight(root.right)+1;
//    }
        /*
    获取二叉树的高度
    */
    int getHeight(TreeNode root) {
         if(root==null) return 0;
         int left = getHeight(root.left);
         int right = getHeight(root.right);
          return left>right
            ?left+1:right+1;
    }


//    // 检测值为value的元素是否存在
//    TreeNode find(TreeNode root, char val) {
//        if(root == null) return null;
//        if(root.val == val) return root;
//        find(root.left,val);
//        find(root.right,val);
//        return root;
//    }


    //层序遍历
    void levelOrder(TreeNode root) {
        if(root == null) return;
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        while(!queue.isEmpty()){
            TreeNode cur = queue.poll();
            System.out.print(cur.val+" ");
            if(cur.left!=null) {
                queue.offer(cur.left);
            }
            if(cur.right!=null) {
                queue.offer(cur.right);
            }
        }

    }

}